The man was rushed to hospital in critical condition where he underwent surgery.
Paramedics said it was a "remarkable" survival story.
The 17-year-old was trying to find his surfboard when the shark attacked him.
Andrew Sharpe was killed by a great white shark while surfing with friends on October 9.
Officials said the shark responsible for the attack was a six-foot-long oceanic whitetip.
"I look over, and I see a dorsal fin! I said 'oh man, that thing's coming right towards me,'" Erik "Marty" Martynuik said of his suspected shark encounter in waters off Emerald Isle, Carteret County.
The shocking footage shows the exact moment of the fatal encounter, with the large ocean predator caught on camera quickly grabbing the sea lion and thrashing its body from side-to-side.
The new "20/20" special chronicles Paige Winter's recovery after being attacked by a shark in 2019. It follows her through receiving a prosthetic leg, as well as important high school milestones.
The tooth measures around 1.8 inches long and 1.1 inches wide.
The man suffered severe injuries to his leg and paramedics were unable to save him.
The woman's swimming partner said "many years of New York self-defense classes" helped her wrestle her hand from the animal's mouth.
The couple were surfing off Shelly Beach, Port Macquarie, in New South Wales on a stretch of Australian coast that has seen three shark attacks this year.
A surfer in Florida was attacked by a shark on Friday.
Witnesses said other surfers rushed to his aid at the time of the attack.
Beach safety officials said the shark bite was the third such incident recorded this year in Volusia County.
The 29-year-old woman told local reporters "I still love sharks. Sharks are beautiful," on her way to the hospital.
The fifteen-year-old boy died after a shark injured his leg while surfing in New South Wales.
"They did everything they could to try and save his life, but despite their best efforts, were unable to do so," a local ambulance inspector said.
The wildlife worker was airlifted to hospital but his injuries proved fatal.
Nick Minogue and a friend were out on the water near Pauanui Beach in New Zealand when the shark attacked.
Ocean safety officers have reported the possible sighting of three tiger sharks of at least 10 feet in length, with at least one reported to have "aggressively" chased a group of paddle boarders.
"I think his whole foot was in the shark's mouth, and you could see the bite mark on the top and bottom of his foot," said a friend of the victim. "Must have been maybe a five or six-foot shark."
A German tourist has suffered severe leg injuries in a possible shark attack on a beach in southern Thailand.
A 26-year-old surfer has suffered a foot injury "possibly from a shark" off the coast of North Carolina, local authorities have reported.
"She had a confrontation with what we believe is a lemon shark and managed to get her foot into the shark's mouth somehow," a LifeFlight rescue team spokesperson said.
Katie Milligan said she and Gary Jonhson have both "watched with dismay" at the reduction of fish stocks over the years following fatal shark attack.
Investigators said the incident took place close to Cull Island near West Beach in the Shire of Esperance in Australia. Rescue officials said they are "still searching the ocean for the victim."
Authorities said the man, who is in his 30s, was bitten on the leg while in waters off the coast of North West Island in Queensland, Australia.